This invention relates generally to inkjet printing mechanisms, and in particular to techniques for maintaining inkjet printhead at its optimal conditions.
Inkjet printing mechanisms use pens which shoot drops of liquid colorant, referred to generally herein as xe2x80x9cink,xe2x80x9d onto a media sheet. Each pen has a printhead formed with very small nozzles through which the ink drops are fired. To print an image, the printhead is propelled back and forth across the media sheet, shooting drops of ink in a desired pattern as it moves. The particular ink ejection mechanism within the printhead may take on a variety of different forms known to those skilled in the art, such as those using piezoelectric or thermal printhead technology.
To clean and protect the printhead, typically a xe2x80x9cwiper assemblyxe2x80x9d mechanism is mounted within the housing of the printing mechanism so the printhead can be moved over the assembly for maintenance, specifically for wiping off ink residue as well as any paper dust or other debris that has collected on the printhead.
During the wiping process, there are risks that due to the wiping force, inks removed from the printhead may splash onto a pen-interconnect area where the printhead is electrically connected to the electrical components of the printing mechanism through conventional interconnects. The splash of ink onto the pen-interconnect area may cause an electrical short between the printhead and the interconnects and consequently a failure of the printhead.
Therefore, there is a need for an improved printhead wiping mechanism which reduces the risk of splashing ink onto undesired areas during a wiping process.
According to an aspect of the present invention, a method for wiping a printhead of an inkjet printing mechanism is provided. The printhead surface defines a printhead plane. In the method, firstly a wiper is moved substantially parallel to the printhead plane for wiping a first portion of the printhead surface. After the first portion of printhead surface is wiped, the wiper is moved away from the printhead plane for wiping a second portion of the printhead surface.
According to a second aspect of the invention, a wiper assembly is provided for wiping a printhead of an inkjet printing mechanism having a chassis, with the printhead on a carriage supported by the chassis for moving to a wiping position, and with the printhead surface defining a printhead plane. The wiper assembly has a frame which defines a first and second guide tracks connected thereto. The first track extends substantially parallel to the printhead plane, while the second track extends away from the printhead plane. The wiper assembly also has a platform movable along the tracks and a wiper mounted on the platform for wiping the printhead when the printhead is in the wiping position.
According to a further aspect of the invention, an inkjet printing mechanism includes a chassis and a printhead on a carriage supported by the chassis for moving to a wiping position. The printhead surface defines a printhead plane. The inkjet printing mechanism further includes a wiper assembly that has a frame which defines a first and second guide tracks connected thereto. The first track extends substantially parallel to the printhead plane, while the second track extends away from the printhead plane. The wiper assembly also has a platform movable along the tracks and a wiper mounted on the platform for wiping the printhead when it is in the wiping position.